1. Field of the Invention
The present invention relates to a method for planning a manufacturing process, and more particularly to a method for planning a semiconductor manufacturing process based on users' demands.
2. Description of Related Art
As shown in FIG. 1, a conventional method for planning a semiconductor manufacturing process includes the steps of:
Step S10: establishing a genetic algorithm model and inputting data into the genetic algorithm model, wherein the data represents the manufacturing type of each wafers that is within a group of wafer lot that is to be manufactured;
Step S20: executing genetic algorithm actions which include coding, crossover, reproduction, mutating, decoding, and so on;
Step S30: determining whether or not a defined number of the generations of the genetic algorithm model has been reached, if yes, executing the step S40; if no, jumping back to the step S20; and
Step S40: defining the chromosome in the genetic algorithm model, which has the smallest value of a fitness function, to be the optimum chromosome, and selecting the optimum chromosome of the generation to be the basis for planning the manufacturing process, wherein the optimum chromosome represents the manufacturing type of each wafer, the manufacturing order of each wafer, and the manufacturing allocated tool of each wafer.
However, the conventional method for planning a semiconductor manufacturing process has the following shortcomings: when users must consider a plurality of performance indexes, the fitness function of the genetic algorithm model is formed by adding a plurality of cost functions multiplied by their own weight, and each cost function respectively represents a kind of performance index and it is very difficult to define the weight of each cost function. If the definition of the weight of any cost function is not accurate, then the result would not meet users' demands, and furthermore, each user has his different demands and it must change the weights when the users' demands are different, which is very inconvenient.
Hence, the inventors of the present invention believe that the shortcomings described above are able to be improved and finally suggest the present invention which is of a reasonable design and is an effective improvement based on extensive research and thought.